The field of this disclosure relates generally to the inspection of rotor blade tips and, more particularly, to a method and a system for use in inspecting blade tip clearance in a turbine engine.
At least some known turbine engines include a rotor assembly including a plurality of rows of rotor blades. Each rotor blade extends radially outward from a blade platform to a tip, and a flow path casing extends substantially circumferentially around the rotor assembly, such that a tip clearance is defined between each respective rotor blade tip and the casing. The tip clearance is designed to be a minimum, while being sized large enough to facilitate rub-free engine operation through a range of available engine operating conditions. During operation, engine performance may be influenced by the tip clearance between the rotor blade tips and the casing. Specifically, if the clearance increases, leakage across the rotor blade tips may adversely limit the performance of the engine.
Accordingly, it is often desirable to inspect the clearance between the casing and the rotor blade tips in a turbine engine to assess performance characteristics of the engine. In at least some known clearance inspection systems, the tip clearance of each rotor blade is measured manually. Such inspection techniques are time consuming and may be unreliable because of variability in measurements from operator to operator due to different measuring devices and/or different clearance inspection techniques.
Moreover, because of the increased time required to manually inspect the engine and because of the high degree of variability possible in clearance measurements performed by different operators, the quality of at least some known engine performance data may be insufficient to make fundamental engineering decisions that are required to optimize engine performance and energy output. In that regard, operating an engine at less than optimal performance may adversely impact operating revenues and may increase maintenance costs.